This invention relates to a lawnmower having a tractor and mowers movable up-and-down on the tractor, and, more particularly, it relates to a tractor and mower assembly of the gang type wherein the mowers are movable up-and-down and they maintain a constant horizontally related spacing between the mowers and relative to the tractor.
Lawnmowers which have tractors supporting mowers with up-and-down movement relative to the tractor are known in the prior art. That type of gang mower is shown in U.S. Pat. Nos. 3,511,033 and 3,905,180, which are patents owned by the assignee herein. That art has a tractor pivotally supporting a mower support arm on which mowers are mounted and can move up and down either in response to riding over uneven ground or by powered lift and lowering cylinders connected to the support arms. In those arrangements, the support arms pivot about an axis to cause the extending ends of the support arms, along with the mowers attached to the extending ends, to move up and down along an arc centered about the pivot axis.
Those mowers are commonly reel mowers and they are arranged in side-by-side relationship along one common reel axis and in rows. The mowers will inherently move toward each other during their arcuate up-and-down movement, and there must be sufficient space between adjacent mowers in each row in order to avoid collisions with each other. Therefore, in an arrangement where the mowing mowers are adequately spaced apart in one row, they leave an unmowed swath between adjacent mowers. The mower of another row is thus positioned to mow that unmowed swath, and that mower must be of a length sufficient to mow that unmowed swath, and all the mowers are of that length.
The length of the mowers is determined by the required non-colliding spacing between adjacent mowers, and the mowers must be sufficiently long to permit the required spacing therebetween in order to avoid colliding upon up-and-down movement. To avoid collisions, the mowers must each be of a minimum length.
In contrast to the foregoing, mowers of only a maximum length, that is, a short mower, will best conform to the irregular contour of the ground over which it is riding. That results in a short mower being more efficient in complete and neat mowing, compared to a mower that must be of a longer length, such as that which is long to avoid the collision mentioned above.
Accordingly, it is the object of this invention to provide a gang type lawnmower with a relative short length for each mower in the gang, and thereby provide for improved mowing, compared to the prior art.
Also, when the mower is moving up-and-down by riding and mowing over irregular ground, and when under the control of the lift mechanism, this invention provides for a gang mower wherein the mowers move up-and-down in parallel vertical planes and thereby maintain a constant horizontal distance away from the respective vertical plane on which each mower is located. Thus the mowers avoid colliding with each other. In accomplishing this objective, the mowers are supported to avoid being moved laterally relative to each other and the tractor, in addition to supporting the mower for up-and-down movement.
Still further, the aforementioned object is accomplished automatically by the lawnmower assembly itself, and operator control or attention is not required.
Still further, the mowers of this invention are operatively maintained in their respective mowing positions relative to the tractor such that they mow along one vertical plane even though they are riding up-and-down over irregular or contoured ground, and they therefore do not move horizontally toward and away relative to the tractor, and the method is such that the mowers mow only in swathes parallel to the tractor, and they do not move toward each other.
This invention accomplishes the aforementioned and does so in conjunction with power lift mechanism which can control up and down movement of the mowers and which does not hinder the above-mentioned horizontal positioning of the mowers.
This invention employs a floating pivot which achieves the mower placement mentioned, and the entire arrangement is of a sturdy construction to provide the optimum pivotal support of the mower relative to the tractor.